In recent years, the wireless tag system is attracting the attention of users. The wireless tag system is a system in which a wireless tag including an IC chip and an antenna is mounted to an article, and ID information stored in a memory of the IC chip is contactlessly read by a wireless tag communication device.
In an exemplary system using the wireless tag, the wireless tag holding an individual ID is attached to the article. The wireless tag communication system is used to search for a specific wireless tag within an area with a plurality of such articles.
As a method for searching the wireless tag, JP-A-2007-088743 discloses a wireless tag information reading device. This wireless tag information reading device communicates with a wireless tag using a wireless communication unit to obtain tag identification information of the target wireless tag. Then, the device controls the transmission output of the wireless tag information reading device to increase/decrease the communication distance, and tries to obtain the tag identification information using the wireless communication unit once again. The device detects the location of the wireless tag by repeating these operations.
JP-A-2007-088743 thus describes a method for detecting the location of the wireless tag by adjusting the transmission output. However, when the wireless tag is located several 10 cm or less from the device and the transmission output is set to a minimum output sufficient for reading the information of the wireless tag, this method might read information of a wireless tag other than the target wireless tag, affected by the type of the tag or installing environment, in spite of the immediate vicinity of the target tag. That is, the method might recognize a wrong tag as the target wireless tag.